Field of the Invention
The present invention relates to a method for building construction industry, and more particularly to a method for hanging conduits and the like from the underside of an overhead metal deck.
Discussion of the Background
It is standard practice in the construction of commercial buildings to use corrugated metal decking as the floor of each story of a building. It is also common practice to suspend items below the decking for the purpose of connecting to suspended utility loads, such as service elements, including conduits, pipes, ducting, systems and the like (referred to herein collectively as a “conduit”).
FIG. 1A is a top view of a prior art metal decking 10 and FIG. 1B is a sectional view 1B-1B of FIG. 1A, illustrating a prior art hanger 1 attached to the underside of the prior art metal decking. Example of metal decking 10 include, but are not limited to, VERCO (VERCO DECKING, INC., Phoenix, Ariz.) models PLW2, W2 FORMLOK™, PLW3, or W3 FORMLOK™.
Metal decking 10 is typically formed from one or more metal sheets of 16-22 gauge formed into a corrugated structure and which may include a concrete on one side of the metal. Thus, for example, FIG. 1A shows metal decking 10 as having a width W and a length L, and including a number of features that extend the length of the decking. Specifically, metal decking 10 is shown as having a plurality of generally horizontal upper flutes 13 with width WU, a plurality of generally horizontal lower flutes 15 a distance D from the upper flutes and having a width WL, and ribs 16 and 17 that connect adjacent lower flutes. Metal decking 10 is shown, in FIG. 1B, as including concrete 12 which is poured over the top of the metal decking.
The internal portions of decking 10 may be considered to include a plurality troughs 14 having a width that varies from width WU at an upper end to width WT at a lower end, which is formed by a pair of adjacent and opposing and mutually facing ribs 16 and 17 and the upper flute 13 that is in between the pair of ribs.
Flutes 13 and 15 and ribs 16 and 17 are generally planar, with the flutes horizontal and the ribs being either sloped, as shown in FIG. 1B or vertical. In certain embodiments, flutes 13 and 15 and ribs 16 and 17 may include indentations, vent holes, undulations, corrugations, or grooves. FIG. 1B shows, for example, that a rib 16 includes groove 18 and that a rib 17 include groove 19, where the grooves extend along the length L of metal decking 10.
It is a typical commercial building construction practice to attach hangers to the underside of overhead metal decking filled with hardened concrete by drilling a hole through the metal decking and hardened concrete, and installing a concrete anchor into the hole in the concrete. FIG. 1B shows a prior art hanger 1, which includes a concrete anchor 3 supported by concrete 12, and a metal hanger 2 attached to the concrete anchor 3.
While prior art hangers, such a hanger 1, are widely used, there are several problems associated with such hangers. First, attaching the hangers involves drilling through two types of material—metal and concrete. This type of operation is noisy and can cause vibrations of the deck structure. While this may not be an issue for new construction, it can be problematic for retrofitting structures, where tenants may be occupying the building.
In addition, drilling or otherwise opening a hole in concrete fractures the concrete and reduces the strength of the concrete for some distance in the concrete. Thus one may have to space the anchors sufficiently far apart to provide sufficient structural support for the anchors.
There is a need in the art for a hanger device and method that is easier to attach to a metal decking. Such a device and method should be able to support sufficient weight to permit the hanging of conduits, should be easy to attach to the underside of metal decking, should involve reduced noise and vibration over prior art techniques, and should allow a user to space the hangers closely. Such a device and method should also be usable for metal decking that does not include concrete reinforcement.